Darkstar: The Java Game Server

Book Description

So, you have a great idea for the next big multiplayer game. Maybe
it's a virtual world based on your favorite sci-fi television show.
Or maybe it's an online bowling league for you and your friends.
Regardless, the challenge of building a networked multiplayer
computer game goes far beyond having a great idea. It can be so
significant that it prevents great games from becoming
reality.
Darkstar breaks down this barrier of complexity. It provides an
easy-to-use library of functions that handles the challenging
aspects of networked game development for you. Further, it provides
a robust, industrial-strength server that can scale with your game
as it grows in popularity. With Darkstar, you can quickly turn your
idea for a multiplayer game into a (virtual) reality.